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Re: [TowerTalk] dxengineering U-bolts froze??

To: towertalk@contesting.com
Subject: Re: [TowerTalk] dxengineering U-bolts froze??
From: Michael Tope <W4EF@dellroy.com>
Reply-to: "Tower and HF antenna construction topics." <towertalk@contesting.com>
Date: Tue, 13 Apr 2010 05:59:06 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 4/13/2010 5:37 AM, Bob AD5VJ wrote:
> I like dxengineering parts; however, I installed my new th6dx this last
> weekend with the help of the Azle Ham Club here locally. After taking down
> my Hornet Tribander I was disassembling the Hornet from the mounting plate
> that I bought from dxengineering.
>
> I bought it with the recommended stainless steel U-bolt clamps they sell
> when I put the Hornet up. It was up less than a year on the tower. While I
> was loosening a couple of the U-bolt from the mast, the nut holding a couple
> of the U-bolts became very hard to take off until I had to place the
> assembly in a vice to get enough torque on my wrench to finally get the nut
> off along with using a spray lubricant.
>
> The threads are ruined on the nut and the U-bolt since it seemed to cross
> thread as it came loose for no apparent reason.
>
> I would have hated to have been trying this on top of the tower hanging from
> a strap trying to get it apart.
>
> Has anyone else had a problem like this, I remember it wasn't hard to
> tighten when I assembled it as it went on very easily, just taking it off
> was very difficult.
>
> 73,
> Bob AD5VJ
>
>    

Hi Bob,

Are these stainless steel U-bolts? If so, they probably seized up. This 
is nothing that would be unique to DX Engineering's stainless steel 
products. It is simply a common property of stainless steel hardware. 
Whenever you use stainless steel hardware you need to coat the threads 
with some kind of anti-seize compound prior to installation. Otherwise, 
the SS nuts can fuse to the mating thread when they are subjected to 
pressure under load. This is often referred to as "galling". I had the 
exact same thing happen to me when I was installing a Cushcraft 2 
element 40M antenna for a local club a few years back. Very annoying 
when you are up in the air on a tower and the only way to get a U-bolt 
off is with a hacksaw :-)  If you check the TT archives you'll find 
quite a bit of discussion on this subject.

73, Mike W4EF..........

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